Currently scuba fins are generally formed of a single piece of material of a fixed length. This creates extra bulk when not in use and inhibits normal land-based activities like walking or running because of the length of the blade extending past the toes.
Furthermore, different lengths of fin blade provide different benefits while swimming; a longer blade with more surface area provides more thrust but requires more effort to use, while a smaller blade provides less thrust but requires less effort. Swimmers may therefore wish to possess several different fins for a variety of swimming environments.
Finally, the foot pocket area of a fixed swim fin is not adjustable, meaning that different fins must be produced for different sizes of foot.